Currently the M2 Bradley Fighting Vehicle has two 4-tube smoke grenade dischargers mounted on the outside of the vehicle. One of the dischargers is mounted on the left side of the vehicle and the other on the right side of the vehicle. There is an arming switch and a fire control button on the inside of the vehicle which the operator can readily reach. After the operator arms the system, which is nothing more than throwing a toggle switch, a +24 volts direct current potential is applied to one side of a fire control push button. This push button is then depressed to close the circuit and send the +24 VDC unto two discharger activate wires. One of the activate wires goes to the left 4-tube discharger unit and the other activate wire goes to the right side 4-tube discharger unit.
The problem with these prior art grenade smoke dischargers was that they did not provide sufficient smoke screening capability for the threat under consideration. The new requirement necessitated a doubling of the capacity without changing the existing control wiring harness or the control box and that the system be nuclear, biological and chemical hardened. Doubling the capacity to meet the new threat required the prior art existing 8 launch tubes (4 left and 4 right) to be fired as salvo A, and a second group of 4 left and 4 right to be fired as salvo B. The retrofit condition specified that both salvos A and B must be controlled using only the existing single supply wire.